1. Field of the Invention
The present invention relates to a method for manufacturing semiconductor structures.
2. Description of the Prior Art
Conventional planar metal-oxide-semiconductor (hereinafter abbreviated as MOS) transistor has difficulty when scaling down to 65 nm and below. Therefore the non-planar transistor technology such as Fin Field effect transistor (FinFET) technology that allows smaller size and higher performance is developed to replace the planar MOS transistor.
Since the manufacturing processes of the FinFET device are easily integrated into the traditional logic device processes, it provides superior process compatibility. More important, since the FinFET device increases the overlapping area between the gate and the substrate, the channel region is more effectively controlled. This therefore reduces drain-induced barrier lowering (DIBL) effect and short channel effect. In addition, the channel region is longer under the same gate length, and thus the current between the source and the drain is increased.
However, the FinFET device still faces many problems. For example, because the fin structures include a thin and slim configuration, it is always difficult to improve process control. There is therefore a continuing need in the semiconductor processing to improve the process control and to obtain the fin structures having desirably expected profile.